Wear-resistant rollback

ABSTRACT

A cylinder lock comprising a sliding element with a longitudinal cavity within a cross-sectionally rectangular frame; a strong recoil spring in the cavity intermediate the frontal plate of the sliding element and a shoulder longitudinally opposed thereto; a bolt connected to the sliding element through a rod about which is positioned a pressure spring for independent displacement of the bolt from the sliding element; and a pair of wear-resistant plates enclosing the shoulders of the sliding element and the ends of the pawl with folded extremities.

I United States Patent [111 3,806,177 Rivadossi Apr. 23, 1974 [54] WEAR-RESISTANT ROLLBACK 2,759,751 8/1956 Kaiser 292/l69.19 X

, 57 8 [76] Inventor: Bianca Pilottelli Rivadossi, 2 803 9 [1957 George 292/169 23 X I Agnosine, Italy Primary Examiner-Joseph H. McGlynn [22] Flled: 1972 Assistant Examiner-Richard P. Tremblay [21] App]. No.: 284,623

[57] ABSTRACT [30] Foreign Application Priority Data Se t 2 1971 Italy 5197! A cylinder lock comprising a sliding element with a p v longitudinal cavity within a cross-sectionally rectangu- [52] U S. Cl 292/169 23 292/1310 38 292/DIG 52 lar frame; a strong recoil spring in the cavity interme- [511 Cl Eosc n2 diate the frontal plate of the sliding element and a [58] Mei! 1 169 12 shoulder longitudinally opposed thereto; a bolt con- 292/169 13 169 nected to the sliding element through a rod about 5 which is positioned a pressure spring for independent 6 5 displacement of the bolt from the sliding element; and a pair of wear-resistant plates enclosing the shoulders [56] References Cited of the sliding element and the ends of the pawl with UNITED STATES PATENTS folded extremmes' 2,846,255 8/1958 Wardwell 292/169.19 X 2 Claims, 5 Drawing Figures WEAR-RESISTANT ROLLBACK FIELD OF THE INVENTION The present invention relates to improvements in cylinder locks.

THE PRIOR ART In conventional cylinder locks, the sliding element which is engaged by the rotating cammed pawls associated with the stem of the handle for displacing the lock bolt or plunger, is generally urged by a relatively weak recoil spring and, in almost all cases, the sliding element of the lock and the bolt constitute a single member and are urged by such recoil spring so that they are displaced always concurrently, even when the bolt is not acted upon directly by the handle, due to the contact of the bolt against the striking plate.

Because of such arrangement in these conventional locks, several disadvantages become immediately discernible, that is, the handle, especially if it is a heavy one, does not always return to its precise neutral position because of the insufficient recoiling action of the spring and the spring, being overloaded, does not permit readily the re-entry of the bolt without a turning of the handle during the closing of the door.

Furthermore, in conventional locks, the cam check lock engages directly the sliding element with the result that, since both members are generally constructed of the same material, such as brass, there is an accelerated wear of the contact surfaces and a consequently undesirable rapid alteration in the normal operation of the lock.

SUMMARY OF THE INVENTION The above mentioned disadvantages are eliminated by the lock of the present invention, the lock comprising: a sliding element having a longitudinal cavity therein and being urged by strong recoil spring positioned between a frontal plate of the sliding element and a fixed shoulder which is integral with the body of the lock; a bolt which is engaged by a suitable pressure spring and is guided on the sliding element so as to be displaced therewith when the handle of the lock is acted upon, but retaining the ability of independent axial displacements when contacting the striking plate on the door; and a pair of wear-resistant plates, made of strong material such as, for example, case-hardened steel, said plates being positioned so as to enclose the pawl associated with the stein of the handle and, particularly, safeguarding against wear those contact surfaces between the pawl and the sliding element.

It is, therefore, the main object of the present invention to provide a cylindrical lock which comprises a pressure spring capable of insuring the return of the handle of the lock to its original neutral position irrespective of the weight thereof.

It is another object of the invention to provide a lock which is long lasting and which prevents the wear of the contact surfaces between the pawl and the sliding element of the lock and allows the bolt to have axial displacements independently of the sliding element.

It is still another object of the invention to provide a lock wherein the strong recoil spring acting on the sliding element is interchangeable with a less loaded spring suitable when the lock is provided with a knob rather than a heavy handle.

THE DRAWINGS These and other objects and advantages of the invention will become apparent from the following detailed description thereof and from the accompanying drawings, in which:

FIG. 1 is a perspective view of the lock of the invention;

FIGS. 2 and 3 are sectional elevational views of the assembled lock, showing the bolt displaced, respectively, outwardly and inwardly;

FIG. 4 is a detailed view of the section of the lock containing the wear-resistant plates; and

FIG. 5 is a sectional view taken in the direction of arrows A-A of FIG. 4.

DETAILED DESCRIPTION OF THE INVENTION Referring now to the accompanying drawings, the lock of the invention comprises a cylindrical body 1 with a frontal plate 2 and formed of two halves assembled into a single entity. In the body 1 there is positioned for axial displacement therein a sliding element 3 having a substantially rectangular cross-sectional frame and defining a cavity 4. In cavity 4 there is positioned a strong recoil spring 5 which operates between a frontal striking plate 6 of the sliding element 3 and a rigid shoulder 7 integral with one of the halves of the body 1. A rod 8 is associated with the frontal plate 6 of the sliding element 3 with ability of axial sliding motion therewithin. Rod 8 is integrally fixed to a bolt or plunger 9 of the lock and is provided with a terminal arresting ring 10 for preventing the disengagement of the rod 8-from the sliding element 3 and for allowing the axial displacement of the bolt 9 toward the inside of the lock as element 3 slides.

On the rod 8 is also mounted a suitable pressure spring 11 to allow the axial displacement of'the bolt 9 upon contact with the door striking plate (not shown), independently of the sliding motion of element 3. At the extremity 12 of the sliding element 3, opposed to the extremity near the bolt 9, there is provided a pawl 13 with a radially protruding cam 14 and with a cross-sectionally square opening 15, which opening is associated with the stem of the lock handle (not shown). The pawl 13 is positioned within the cavity 4 of the sliding element 3 so that the extremities 14' of the protruding cam 14 act in conventional fashion upon the corresponding shoulders 16 provided in the sliding element 3 of the lock.

Intermediate the inner surface of the sliding element 3 and the lateral surface of the pawl 13 which is not contacted by the radial cam 14, there is provided a wear-resistant U-shaped plate 17 constructed of a suitable material such as, for example, case-hardened steel. The ends 18 of the plate 17 are folded so as to enclose therein the shoulders 16 of the sliding element 3. On

the pawl 13, on the other hand, there is mounted a second wear-resistant plate 20 positioned solidly within a seat 19 provided at the base of the radial cam 14. The ends 21 of this second plate 20 are folded over so as to envelope and to be in firm contact with the extremities 14' of the cam 14 as well as with the ends 18 of the plate 17.

By acting upon the lock handle (not shown), the pawl l3 effects an angular displacement with the resultant action of the radial protruding cam 14 upon the shoul ders 16 of the sliding element 3, which consequently is displaced axially and concurrently with the bolt 9 against the spring 5. Upon termination of the action on the handle of the lock, the spring returns the sliding element 3 and, consequently, the stem of the handle to its original neutral position.

What is claimed is:

1. in a cylinder lock comprising a cylindrical body having two halves assembled to one another into a single entity, a pawl with radially protruding cam, a sliding element within the body with shoulders acted upon by the pawl, a bolt connected with the sliding element and capable of axial displacements concurrently therewith, the improvement comprising a frame-shaped sliding element defining a cavity therein; a frontal plate on said sliding element; a shoulder provided on the body of the lock spaced from said frontal plate; a recoil spring positioned intermediate said frontal plate and said shoulder on said body; wear-resistant plates enclosing and protecting the radially protruding cam of the pawl from frictional wear against the shoulders upon which the cam acts; the pawl being positioned within said cavity and wherein a'first wear-resistant plate is mounted intermediate said sliding element and the pawl on the side opposite the cam, said first plate having its extremitiesfolded over so as to enclose the shoulders of said sliding element, and wherein a second wear-resistant plate is positioned seated within the cam, said second plate having its extremities folded over so as to enclose the ends of the cam, the extremities of said first and second plates being direct contact with one another.

2. The improvement of claim 1, wherein said bolt comprises a rod associated with said frontal plate of said sliding element so as to effect axial displacements independently of said sliding element, said rod having thereabout a pressure spring. 

1. In a cylinder lock comprising a cylindrical body having two halves assembled to one another into a single entity, a pawl with radially protruding cam, a sliding element within the body with shoulders acted upon by the pawl, a bolt connected wiTh the sliding element and capable of axial displacements concurrently therewith, the improvement comprising a frame-shaped sliding element defining a cavity therein; a frontal plate on said sliding element; a shoulder provided on the body of the lock spaced from said frontal plate; a recoil spring positioned intermediate said frontal plate and said shoulder on said body; wear-resistant plates enclosing and protecting the radially protruding cam of the pawl from frictional wear against the shoulders upon which the cam acts; the pawl being positioned within said cavity and wherein a first wear-resistant plate is mounted intermediate said sliding element and the pawl on the side opposite the cam, said first plate having its extremities folded over so as to enclose the shoulders of said sliding element, and wherein a second wear-resistant plate is positioned seated within the cam, said second plate having its extremities folded over so as to enclose the ends of the cam, the extremities of said first and second plates being direct contact with one another.
 2. The improvement of claim 1, wherein said bolt comprises a rod associated with said frontal plate of said sliding element so as to effect axial displacements independently of said sliding element, said rod having thereabout a pressure spring. 